Substation ringer having permanent magnet armature



Aug. 23, 1949. s. R. SMITH 2,479,703

SUBSTATION RINGER HAVING PERMANENT MAGNET ARMA'IURE Filed June 7, 1947INVENTOR SIDN EY REYNELL SMITH ATTORNEY Patented Aug. 23, 1949SUBSTATION RINGER HAVING PERMANENT MAGNET ARMATURE Sidney Reynell Smith,Liverpool, England, assignor to Automatic Telephone & Electric CompanyLimited, company Liverpool, England, a British Application June '7,1947, Serial No. 753,291 In Great Britain June 21, 1946 Claims.

The present invention relates to signalling devices and is moreparticularly concerned with ringing arrangements or ringers which areparticularly applicable for use in telephone and like signallingsystems.

The main object of the invention is to provide, in a ringer employing apermanent magnet armature, arrangements whereby the size of the ringeris reduced, its operational efiiciency is increased and the adjustmentsare simplified.

According to one feature of the invention, the bell hammer is rigidlyfixed to the permanent magnet armature in such a manner as to eliminaterelative movement between the hammer and armature at the moment ofimpact with the According to a further feature of the invention, thepermanent magnet armature is mounted in such a position with relation tothe point of impact of the hammer with the gong that its centre ofgravity moves substantially towards the point of impact whereby inconjunction with a rigid connection between the armature and the hammer,the impact has behind it the full momentum of the moving structure.

According to yet another feature of the invention. a non-magnetic plateis pivoted at one end and at the other end is provided with projectionswhich act as hammer heads, the permanent magnet armature being rigidlysecured to said plate in a position intermediate to said projections,suitable electromagnetic means being provided which when energised byalternating current cause an arcuate reciprocating motion of the movingstructure about the pivots.

These and other features of the invention will be better understood fromthe following description of one embodiment shown in the accompanyingdrawings in which Fig. 1 shows a partial view of the ringer,

Fig. 2 shows a sectional view along the line A-A of Fig. 1 and Fig. 3shows a sectional view along the line BB of Fig. 1.

A mounting plate 38 is provided for carrying the gongs 32, 33 and thetwo electromagnets 10, H. The gongs are secured to pillars 34, 35 bymeans of screws 36, 31, the screws also serving to secure in position abridge having downwardly extending flanges 3|, shown in Figs. 1 and 3.

The electromagnets 10, II are provided with polepieces l2, l4 and l3, 15respectively, the polepieces being secured to the ferrous metal cores 39and 40 of the electromagnets by means of screws l6, l8, l1 and 19. Thefree ends of the polepieces are formed of reduced portions 20, 2|, Z2and 23 and the windings of the electromagnets are brought out to tags24, 25, 26 and 21. The electromagnets are secured to the underside ofthe mounting plate 38 by securing the polepieces thereto by means ofscrews M, the polepieces passing through suitable slots in the mountingplate.

The downwardly extending flanges 3| of the bridge form bearings for apivoted member 30 which carries a plate or hammer 28 of non-magneticmaterial to which is secured the permanent magnet 29. As shown in Fig.1, the hammer 28 is provided at its lower end with oppositely extendingprojections which form the hammer heads. The permanent magnet iscylindrical in shape and is made of high quality magnet steel while itis magnetised to form N and S poles as shown in Figs. 2 and 3. In thenormal condition of the ringer, the permanent magnet assumes asubstantially symmetrical position with respect to the two pairs ofpolepieces, as best shown in Fig. 1. The windings of the electromagnetsare so connected that, when the electromagnets are energised by analternating current, two dissimilar poles are formed at each end of thepermanent magnet. For example, referring to Fig. 2, during one halfcycle of the alternating current, north and south poles might be formedat polepieces 2! and 23 respectively when south and north poles would beformed at polepieces 20 and 22 respectively. The armature will thus bemoved to the left while on the succeeding half cycle of the alternatingcurrent, the polarity of the polepieces will be reversed and thearmature will be moved to the right.

It will be appreciated that the invention is not limited to theembodiment described above but that alternative constructions arepossible. For instance, one electromagnet only may be employed togetherwith a plain ferrous metal return path provided with polepieces theefiect of which is to cause the armature to assume a normal positionwhich is not symmetrical with the polepieces associated with theelectromagnet. Hence when the electromagnet is energised, the additionalflux becomes eiiective to move the armature to one side or the other andthe subsequent flux reversals then maintain a regular swing.Alternatively the armature may be spring-biased to a non-symmetricalnormal position.

I claim:

1. In a ringer having gongs, a non-magnetic element pivoted at one endand having striking faces at opposite sides of the other end, apermanent magnet disposed between said faces, electromagnets havingpolepieces disposed on opposite sides of said permanent magnet,energization of said electromagnets causing" movement of said elementlasa pendulum to cause said faces to alternately strike said gongs.

2. A ringer such as claimed in claim 1 in which said permanent magnetmaintains said striking faces of the element spaced from said gongs whensaid electromagnets are not energized.

3. A ringer such as claimed inclaim 11in which said striking facesalways follow eachmovement of said permanent magnet.

4. In a signalling device, a permanent magnet armature, a non-magneticgong hammer being pivotally mounted projections at the other end forserving as hamat one end and provided with mer heads, said armaturebeing rigidly secured Y to said gong hammer at a position equidistantbetween said "hammer heads, means for causing said armature to move saidgong hammer in simple harmonic motion about said pivot.

5. Ina signallingdevice, a pivoted gong hammer, aipermanent magnetsecured to one end of pieces adjacent to each end of 2 saidelectromagnets being so connected that when energized by alternatingcurrent the two polesaid permanent magnet have dissimilar polarities.

SIDNEY REYNELL SMITH.

REFERENCES CITED The following references are of record in the file. ofthis patent:

UNITED STATES PATENTS Number Name Date 229,279 t See et a1. June 29,1880 "276,136 'Drawbaugh Apr. 17, 1883 1,034,964.- Bowman Aug. 6, 19122,323,803 Dickten et al July 6, 1943 2,265,066 Devaux Dec. 2, 1941

